Inhaler controller

ABSTRACT

An inhaler controller includes a first path configured to connect a first voltage terminal to which a first voltage is supplied and a connection terminal to which a heater configured to heat an aerosol source is connected, a second path configured to connect a second voltage terminal to which a second voltage different from the first voltage is supplied and the connection terminal via a resistor, and a measurement circuit configured to measure a resistance value of the heater.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Japanese PatentApplication No. 2020-150100 filed on Sep. 7, 2020, the entire disclosureof which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an inhaler controller.

Description of the Related Art

Japanese Patent Laid-Open No. 2017-501805 discloses an apparatus thatgenerates an aerosol that can be inhaled. This apparatus includes aheating resistive element R_COIL that heats a vapor formation medium inan oven chamber. The heating resistive element R_COIL is also used as atemperature sensor. The apparatus includes switches Q1 and Q2. Theswitches Q1 and Q2 are respectively turned on and off to heat theheating resistive element R_COIL. This forms a current path extendingthrough the switch Q1 and the heating resistive element R_COIL. When thetemperature of the heating resistive element R_COIL is measured, theswitches Q1 and Q2 are respectively turned off and on to form a currentpath extending through the switch Q2, a voltage divider R REF, and theheating resistive element R_COIL. In this state, a voltage V_MEAS at theconnection node between the voltage divider R REF and the heatingresistive element R_COIL is measured.

The apparatus disclosed in Japanese Patent Laid-Open No. 2017-501805uses a common power-supply line for heating the heating resistiveelement R_COIL and for measuring the temperature of the heatingresistive element R_COIL. In this arrangement, when, for example, theoutput voltage of a battery is changed to adjust or change the mode ofheating the heating resistive element R_COIL, the calculation formulafor converting the voltage V_MEAS into a temperature needs to be changedaccordingly.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, it is an object toimprove the permissivity with respect to a change in voltage supplied toa heater for heating an aerosol source.

One aspect of the present invention is directed to an inhalercontroller, and the inhaler controller comprises: a first pathconfigured to connect a first voltage terminal to which a first voltageis supplied and a connection terminal to which a heater configured toheat an aerosol source is connected; a second path configured to connecta second voltage terminal to which a second voltage different from thefirst voltage is supplied and the connection terminal via a resistor;and a measurement circuit configured to measure a resistance value ofthe heater.

The controller can further comprise a cutoff unit configured to cut offa current flowing between the first path and the second path due to adifference between the first voltage and the second voltage.

The cutoff unit can include a diode.

The cutoff unit can be arranged in the second path.

The measurement circuit can include a differential amplifier arranged todetect a voltage drop caused by the heater.

A voltage can be supplied from a node between the second voltageterminal and the cutoff unit to a power supply terminal of thedifferential amplifier.

The differential amplifier can include a first input terminal to which avoltage corresponding to a voltage of the connection terminal issupplied and a second input terminal to which a predetermined voltage issupplied.

The controller can further comprise a protection element connected tothe first input terminal.

The protection element can include one of a Zener diode and a varistor.

The controller can further comprise: a first regulator configured togenerate the first voltage; and a second regulator configured togenerate the second voltage.

The controller can further comprise a processor configured to controlthe first regulator and the second regulator.

The processor can control the first regulator and the second regulatorusing a common enable signal.

The processor can control a magnitude of a voltage generated by thefirst regulator.

The controller can further comprise: a first switch arranged in thefirst path; and a second switch arranged in the second path, wherein theprocessor controls the first switch and the second switch.

The processor can have a period in which a period during which the firstswitch is ON overlaps a period during which the second switch is ON.

According to the above aspect of the present invention, the permissivitywith respect to the change in voltage supplied to the heater for heatingthe aerosol source can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view schematically showing the arrangement of an inhaleraccording to one embodiment;

FIG. 2 is a circuit diagram showing an example of the arrangement of theelectrical components of a controller in the inhaler shown in FIG. 1;

FIG. 3 is a circuit diagram for explaining the arrangement and operationof the electrical components in FIG. 2;

FIG. 4 is a circuit diagram for explaining the arrangement and operationof the electrical components in FIG. 2;

FIG. 5 is a circuit diagram for explaining the arrangement and operationof the electrical components in FIG. 2;

FIG. 6 is a circuit diagram for explaining the arrangement and operationof the electrical components in FIG. 2;

FIG. 7 is a circuit diagram for explaining the arrangement and operationof the electrical components in FIG. 2;

FIG. 8 is a circuit diagram for explaining the arrangement and operationof the electrical components in FIG. 2;

FIG. 9 is a flowchart exemplarily showing temperature control on aheater in the inhaler according to one embodiment;

FIG. 10 is a flowchart exemplarily showing the operation of a protectioncircuit associated with the protection of a power supply;

FIG. 11 is a flowchart exemplarily showing the operation of a processorassociated with the protection of the power supply; and

FIG. 12 is a graph exemplarily showing criteria associated with theprotection of the power supply.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments will be described in detail with reference tothe accompanying drawings. It should be noted that the followingembodiments are not intended to limit the scope of the appended claims,and that not all the combinations of features described in theembodiments are necessarily essential to the present invention. Of aplurality of features described in the embodiments, two or more featuresmay arbitrarily be combined. In addition, the same reference numeralsdenote the same or similar parts, and a repetitive description will beomitted.

FIG. 1 schematically shows the arrangement of an inhaler 100 accordingto an embodiment. The inhaler 100 can be configured as an aerosolgeneration device. The inhaler 100 can be configured to provide, to auser via a suction port or a mouthpiece 130, a gas containing anaerosol, a gas containing an aerosol and a flavor material, an aerosol,or an aerosol containing a flavor material in accordance with anoperation requesting the aerosol (to be also referred to as an aerosolrequesting operation hereinafter) such as a suction or inhalingoperation by the user. The inhaler 100 can comprise a controller 102 andan atomizer 104. The inhaler 100 can comprise a holding portion 103 thatdetachably holds the atomizer 104. The controller 102 may be understoodas an inhaler controller. The atomizer 104 can be configured to atomizean aerosol source. The aerosol source can be, for example, a liquid suchas a multivalent alcohol such as glycerin or propylene glycol.Alternatively, the aerosol source may contain a drug. The aerosol sourcecan be a liquid, a solid, or a mixture of a liquid and a solid. A vaporsource such as water may be used in place of the aerosol source.

The inhaler 100 may further comprise a capsule 106 containing a flavorsource 131. The atomizer 104 can include a capsule holder 105 thatdetachably holds the capsule 106. The capsule holder 105 may be includedin the controller 102 instead of the atomizer 104. The flavor source 131can be a molded body obtained by molding, for example, a cigarettematerial. Alternatively, the flavor source 131 may be made of a plant(for example, mint, herb, Chinese medicine, coffee beans, or the like)except the cigarette. A fragrance such as menthol may be added to theflavor source. The flavor source 131 may be added to an aerosol source.The atomizer 104 and the capsule holder 105 may be integrally formed inplace of an arrangement in which the inhaler 100 or the atomizer 104includes the capsule holder 105.

The controller 102 can include electrical components 110. The electricalcomponents 110 can include a user interface 116. Alternatively, thecontroller 102 may be understood to include the electrical components110 and the user interface 116. The user interface 116 can include, forexample, a display DISP (for example, an LED (Light Emitting Diode)and/or an image display such as an LCD) and/or an operation unit OP (forexample, a switch such as a button switch and/or a touch display). Thedisplay DISP may be understood as a notificator that notifiesinformation.

The holding portion 103 of the controller 102 can include a firstelectrical contact C1 and a second electrical contact C2. In a state inwhich the atomizer 104 is held by the holding portion 103, the firstelectrical contact C1 of the holding portion 103 can contact a thirdelectrical contact C3 of the atomizer 104, and the second electricalcontact C2 of the holding portion 103 can contact a fourth electricalcontact C4 of the atomizer 104. The controller 102 can supply power tothe atomizer 104 via the first electrical contact C1 and the secondelectrical contact C2.

The atomizer 104 can include the third electrical contact C3 and thefourth electrical contact C4 described above. In addition, the atomizer104 can include a heater HT for heating the aerosol source, a container125 for holding the aerosol source, and a transport portion (wick) 126for transporting the aerosol source held by the container 125 to aheating region of the heater HT and holding the aerosol source in theheating region. At least part of the heating region can be arranged in achannel 128 formed in the atomizer 104. The first electrical contact C1,the third electrical contact C3, the heater HT, the fourth electricalcontact C4, and the second electrical contact C2 form a current path forflowing the current to the heater HT. The transport portion 126 can bemade of a fiber element such as a glass fiber, a porous material such asa ceramic, or a combination thereof. Note that the means fortransporting the aerosol source held in the container 125 to the heatingregion is not limited to the wick, but a spraying device such as a sprayor a transporting means such as a pump may be used instead.

As described above, the atomizer 104 can include the capsule holder 105for detachably holding the capsule 106. As an example, the capsuleholder 105 can hold the capsule 106 such that part of the capsule 106 isaccommodated in the capsule holder 105 or the atomizer 104 and theremaining part of the capsule 106 is exposed. The user can hold thesuction port 130 with his/her mouth and suck the gas containing theaerosol. Since the detachable capsule 106 includes the suction port 130,the inhaler 100 can be kept clean.

When the user holds the suction port 130 with his/her mouth and performsthe suction operation, as exemplified by an arrow, air flows into thechannel 128 of the atomizer 104 via an opening (not shown). When theheater HT heats the aerosol source, the vaporized and/or aerosolizedaerosol source is transported toward the suction port 130 with the air.In the process in which the aerosol source is transported toward thesuction port 130, the vaporized and/or aerosolized aerosol source iscooled to form fine liquid droplets, thereby promoting aerosolization.In the arrangement in which the flavor source 131 is arranged, theflavor material generated by the flavor source 131 is added to thisaerosol, and the resultant material is transported to the suction port130, thus allowing the user to suck the aerosol containing the flavormaterial. Since the flavor material generated by the flavor source 131is added to the aerosol, the flavor material can be efficientlytransported to the lungs of the user without staying in the oral cavity.

FIG. 2 shows an example of the arrangement of the electrical components110 of the controller 102. The electrical components 110 can include,for example, a power supply BAT, protection circuits 16 and 17, acontrol circuit CC, a first voltage converter 11, a second voltageconverter (second regulator) 12, a third voltage converter (firstregulator) 13, a first switch Q1, a second switch Q2, a first transistor(third switch) Q3, a second transistor (fourth switch) Q4, a measurementcircuit MC, a plug PG, and a bridge circuit BC. Note that a female type(concave type) receptor may be used instead of the male type (convextype) plug PG. The control circuit CC is configured to control theoperation of the controller 102. The control circuit CC can include, forexample, a processor 14, an LED driver 18, an LED 19, a switch 20, apuff sensor 21, and a touch sensor 22. It is possible to use, as thepower supply BAT, for example, a lithium ion secondary battery, alithium ion capacitor, a combination thereof, or another type of powersupply element.

The processor 14 can be formed by, for example, an MCU. The LED driver18 and the LED 19 can form all or part of the display DISP describedabove. The LED 19 is an example of a display. The LED driver 18 candrive the LED 19 in accordance with commands from the processor 14. Thepuff sensor 21 can detect a puff operation by the user. The puff sensor21 may be formed by, for example, a microphone condenser, a flow ratesensor, or one or a plurality of pressure sensors. The touch sensor 22can form all or part of the operation unit OP described above. Thecontroller 102 receives the supply of power from an external powersupply EB via the plug PG. In addition, the controller 102 cancommunicate with an external apparatus (not shown) having the externalpower supply EB via the switch 20 and the plug PG. The processor 14 cancommunicate with the LED driver 18, the switch 20, the puff sensor 21,and the third voltage converter 13 via a communication interface such asI²C communication as one kind of serial communication using SDA (SerialDAta) lines and SCL (Serial CLock) lines. Note that the communicationinterface is not limited to I²C communication, but another type ofserial communication interface such as UART communication or SPIcommunication may be used instead. The switch 20 has an enable terminalEN. A voltage obtained by dividing the voltage applied from the externalapparatus via the plug PG and the protection circuit 16 by resistors R4and R3 can be supplied to the enable terminal EN. When the voltagesupplied to the enable terminal EN exceeds a predetermined level, theswitch 20 can set a connection state (communicable state) between thecommunication interface among the processor 14, the LED driver 18, theswitch 20, the puff sensor 21, and the third voltage converter 13 andthe external apparatus connected to the plug PG. According to anotherpoint of view, when the voltage supplied to the enable terminal ENexceeds the predetermined level, the switch 20 can set a connectionstate (communicable state) between the processor 14 and the externalapparatus connected to the plug PG.

According to one aspect, the electrical components 110 of the controller102 can include a first path P1, a second path P2, and the measurementcircuit MC. The first path P1 electrically connects a first voltageterminal Ti, to which a first voltage V1 is supplied, to a connectionterminal C1, to which the heater HT for heating the aerosol source ofthe atomizer 104 is connected. The second path P2 electrically connectsthe connection terminal C1 to a second voltage terminal T2, to which asecond voltage V2 different from the first voltage V1 is supplied, via aresistor R_(S). The measurement circuit MC measures a resistance valueR_(HTR) of the heater HT. The first voltage V1 is a voltage for heatingthe heater HT. The second voltage V2 is a voltage for measuring theresistance value R_(HTR) of the heater HT. If the heater HT has apositive or negative temperature coefficient characteristic that theresistance value R_(HTR) changes in accordance with the temperature ofthe heater HT itself, the resistance value R_(HTR) of the heater HT hasa strong correlation with its temperature. In other words, the processor14 can acquire the temperature of the heater HT by acquiring theresistance value R_(HTR) of the heater HT using the measurement circuitMC. Controlling the temperature of the heater HT is closely associatedwith the delivery of an aerosol having an intended flavor from theinhaler 100 to the user, and hence is important. The processor 14 maycontrol a current flowing in the first path P1 based on an output fromthe measurement circuit MC that measures the resistance value R_(HTR) ofthe heater HT such that the temperature of the heater HT converges to atarget value or target range. In addition, the processor 14 may cut offthe current flowing in the first path P1 when the temperature of theheater HT exceeds a threshold based on an output from the measurementcircuit MC that measures the resistance value R_(HTR) of the heater HT.

According to this arrangement, even when the first voltage V1 is changedto heat the heater HT, the second voltage V2 for measuring theresistance value R_(HTR) of the heater HT is free from the influence ofthe change. Accordingly, when the first voltage V1 is changed, theprocessing of measuring the resistance value R_(HTR) of the heater HT isalso free from the influence of the change. That is, it is possible toimprove the permissivity with respect to a change in the voltagesupplied to the heater HT for heating the aerosol source. The firstvoltage V1 can be changed in accordance with information representingheating strength as will be described later. Alternatively, the firstvoltage V1 can be changed by changing the design or usage of the inhaler100.

For example, the third voltage converter (first regulator) 13 canprovide the first voltage V1. The third voltage converter 13 cangenerate the first voltage V1 by, for example, using the voltagesupplied from the power supply BAT. For example, the third voltageconverter 13 can be formed by a buck-boost DC/DC converter. Thebuck-boost DC/DC converter may be formed by an IC chip and severalelements (for example, a coil, a transistor, and a diode) connected tothe IC chip. The third voltage converter 13 can be, for example,configured to generate the first voltage V1 in accordance with theheating strength (the heating strength of the heater HT with respect tothe aerosol source) commanded by the user. In this case, the informationrepresenting the heating strength may be provided from the user to theprocessor 14 via the operation unit OP including the touch sensor 22 orthe external apparatus connected to the plug PG. The processor 14 may beconfigured to transmit a command value indicating a voltage valuecorresponding to the information to the third voltage converter 13. Theinformation representing the heating strength can be, for example,specified by the user selecting one of a plurality of modes withdifferent heating strengths. The first voltage V1 can be a voltagehigher than, for example, 2.5 V but is not limited to this. The thirdvoltage converter 13 may be formed by a boost DC/DC converter or buckDC/DC converter instead of the buck-boost DC/DC converter. In order toimplement various heating strengths, the third voltage converter 13 ismore preferably formed by a buck-boost DC/DC converter having thebroadest range of first voltages V1 that can be generated. Note that theconversion efficiency may be improved or the mounting area may bereduced by forming the third voltage converter 13 using a boost DC/DCconverter or buck DC/DC converter depending on the required heatingstrength or the heater HT to be used.

For example, the second voltage converter (second regulator) 12 canprovide the second voltage V2. The second voltage converter 12 cangenerate the second voltage V2 by, for example, using the voltagesupplied from the power supply BAT. The second voltage converter 12 canbe formed by, for example, an LDO (Low DropOut). The second voltage V2can be, for example, 2.5 V but is not limited to this. The secondvoltage converter 12 may be formed by a switching regulator such as theabove DC/DC converter instead of the LDO. Note, however, that the secondvoltage converter 12 is not required to change the value of the voltageto be generated in accordance with the heating strength unlike the thirdvoltage converter 13, and the fixed second voltage V2 is preferablygenerated to stably measure the resistance value R_(HTR) of the heaterHT. In consideration of this point, because there is no need to use thecoil, the transistor, the diode, and the like described above, thesecond voltage converter 12 may be formed by the LDO that can easilyimplement a small-size, low-cost converter. Note that since the LDOdiscards the difference between a voltage (power) supplied and a voltage(power) to be output as heat, it is difficult for the LDO to handle alarge current as compared with a DC/DC converter. Since the currentflowing in the second path P2 is smaller than the current flowing in thefirst path P1, the LDO can be used as the second voltage converter 12.

The processor 14 can be configured to control the third voltageconverter (first regulator) 13 and the second voltage converter (secondregulator) 12 with a common enable signal EN2. In other words, the thirdvoltage converter 13 and the second voltage converter 12 can besimultaneously started, and the operations of the third voltageconverter 13 and the second voltage converter 12 can be simultaneouslystopped. This arrangement can easily start and stop the third voltageconverter 13 and the second voltage converter 12 while suppressing anincrease in substrate size and complexity of wirings. Note also thatsince the timing when the third voltage converter 13 generates thevoltage value V1 is close to or the same as the timing when the secondvoltage converter 12 generates the second voltage V2, synchronizing theoperation of the third voltage converter 13 with the operation of thesecond voltage converter 12 has almost no adverse effect in terms ofpower consumption.

The measurement circuit MC can include the second path P2 and a shuntresistor R_(S) connected in series with the heater HT. Unlike the heaterHT, the resistance value of the shunt resistor R_(S) is almost invariantwith respect to the temperature. In addition, the measurement circuit MCcan include a differential amplifier 15 that detects a voltage V_(HTR)applied to the heater HT. The differential amplifier 15 can be arrangedto detect a voltage drop by the heater HT. In this case, the resistancevalue of the shunt resistor R_(S) is denoted by R_(S), which isidentical to the reference symbol of the resistor. The differentialamplifier 15 can have a first input terminal (for example, anon-inverting input terminal) to which a voltage corresponding to avoltage at the connection terminal C1 is supplied, a second inputterminal (inverting input terminal) to which a predetermined voltage issupplied, and an output terminal. A protection element PE can beconnected to the first input terminal. For example, the protectionelement PE can be configured to prevent a voltage exceeding the secondvoltage V2 from being supplied to the first input terminal. Theprotection element PE can include, for example, a Zener diode orvaristor.

In the second path P2, the second switch Q2 can be arranged in serieswith the shunt resistor R_(S) and the heater HT. The electricalcomponents 110 can include, for example, a cutoff unit BE that cuts offthe current flowing between the first path P1 and the second path P2owing to the difference between the voltage value V1 and the secondvoltage V2. As will be described later, when a period in which the firstswitch Q1 is ON partly overlap a period in which the second switch Q2 isON, a current may flow from the first path P1 to the second path P2. Forthis reason, the cutoff unit BE can protect the second voltage converter12. The cutoff unit BE can include a rectifier element such as a diode.The rectifier element can be arranged such that the direction from thesecond voltage terminal T2 to the connection terminal C1 is the forwarddirection. The second switch Q2 can be controlled by a control signalgenerated by the processor 14. A voltage can be supplied from the nodebetween the second voltage terminal T2 and the cutoff unit BE to thepower supply terminal (voltage receiving terminal) of the differentialamplifier 15. The voltage supplied to the power supply terminal of thedifferential amplifier 15 in this manner is higher by the extent towhich the voltage is free from the influence of a drop in the forwardvoltage of the cutoff unit BE. That is, a different voltage and anoutput voltage in the differential amplifier 15 become difficult tostick to the voltage supplied to the power supply terminal. In addition,it is possible to improve the resolution of the temperature T of theheater HT acquired by the processor 14 by increasing the amplificationfactor of the differential amplifier 15 to prevent the differentialvoltage and the output voltage from sticking to the voltage supplied tothe power supply terminal. That is, the processor 14 can acquire thetemperature T of the heater HT with high accuracy as compared with thecase in which a voltage is supplied from the downstream of the cutoffunit BE to the power supply terminal of the differential amplifier 15 inthe direction in which a current flows in the second path P2. Inaddition, according to the arrangement in which the second voltageconverter 12 outputs the second voltage V2 only when the processor 14acquires the temperature of the heater HT, the differential amplifier 15operates only when necessary, thereby also implementing the power savingof the inhaler 100. In another point of view, the voltage at the secondvoltage terminal T2, that is, the second voltage V2, can be supplied tothe power supply terminal (voltage receiving terminal) of thedifferential amplifier 15.

When the resistance value R_(HTR) of the heater HT is detected, thefirst switch Q1 can be turned off and the second switch Q2 can be turnedon. At this time, letting I_(HTR) be a current flowing in the heater HT,V_(HTR) be a voltage at the first connection terminal C1, and V_(f) be aforward voltage drop at the cutoff unit BE, R_(HTR) is given by equation(1):

R _(HTR) =V _(HTR) /I _(HTR) =V _(HTR)·(R _(HTR) ·R _(S))/(V2−V_(f))  (1)

Equation (1) is transformed into equation (2) that gives R_(HTR).

R _(HTR) =R _(S) ·V _(HTR)/(V2−V _(f) −V _(HTR))  (2)

Letting V_(AMP) be the output voltage of the differential amplifier 15and A be the amplification factor of the differential amplifier 15,V_(AMP) is given by equation (3):

V _(AMP) =A·V _(HTR)  (3)

Equation (3) is transformed into equation (4) that gives R_(HTR).

V _(HTR) =V _(AMP) /A  (4)

Therefore, the resistance value R_(HTR) of the heater HT can be obtainedaccording to equations (2) and (4).

The processor 14 can include an input terminal to which the outputvoltage V_(AMP) of the differential amplifier 15 of the measurementcircuit MC is input and an AD converter that converts an analog signalas a voltage input to the input terminal into a digital signal. Theprocessor 14 can generate a control signal that controls the firstswitch Q1 for controlling heating by the heater HT in accordance withthe information (V_(AMP) in this case) obtained by using the measurementcircuit MC.

The processor 14 can be formed by, for example, an MCU (Micro ControllerUnit). The processor 14 can calculate the temperature of the heater HTaccording to equation (5) based on the resistance value R_(HTR) of theheater HT.

T=T _(ref)+(1/α)·(R _(HTR) −R _(ref))·(1/R _(ref))·10⁶  (5)

where T_(ref) is a reference temperature, R_(ref) is a referenceresistance value, which is the resistance value R_(HTR) of the heater HTat the reference temperature T_(ref), and a is a temperature coefficient[ppm/° C.] of the heater HT. Note that the reference temperature T_(ref)can be set to an arbitrary temperature and is the temperature of theheater HT when the reference resistance value R_(ref) is acquired. Asthe temperature of the heater HT when the reference resistance valueR_(ref) is acquired, the temperature at an arbitrary portion in theinhaler 100 can be used instead. The inhaler 100 can include atemperature sensor (for example, a thermistor TM (to be describedlater)) that measures a temperature. The temperature measured by thetemperature sensor can be set as the reference temperature T_(ref).

FIG. 9 shows a procedure for temperature control on the heater HT in theinhaler 100. The processor 14 performs the temperature control shown inFIG. 9. In step S901, the processor 14 can detect suction (puffoperation) by the user based on an output from the puff sensor 21. Inthis case, the puff sensor 21 can be, for example, configured to detectsuction (puff operation) by the user based on, for example, at least oneof a change in pressure, sound, an air flow, and the operation of theoperation unit OP. Upon detecting suction by the user in step S901, theprocessor 14 starts the third voltage converter (first regulator) 13 andthe second voltage converter (second regulator) 12 by activating theenable signal EN2 in step S902. This allows the third voltage converter13 to output the first voltage V1 from the first voltage terminal T1 andallows the second voltage converter 12 to output the second voltage V2from the second voltage terminal T2. Note that the first switch Q1 needsto be turned on to cause the third voltage converter 13 to output thevoltage value V1 to the first path P1. Likewise, note that the secondswitch Q2 needs to be turned on to cause the second voltage converter 12to output the second voltage V2 to the second path P2. This embodimenthas exemplified the case in which the puff sensor 21 is used to detectthe above aerosol requesting operation. In other words, suction (puffoperation) by the user corresponds to an aerosol requesting operation.Instead of this embodiment, the operation unit OP may be used to detectthe above aerosol requesting operation. In this case, an operation onthe operation unit OP corresponds to the aerosol requesting operation.More specifically, for example, the processor 14 may detect an aerosolrequesting operation as long as an operation on the operation unit OPcontinues.

In step S903, the processor 14 can turn on the first switch Q1. In stepS904, the processor 14 can turn on the second switch Q2. In step S905,the processor 14 can turn off the first switch Q1. In step S906, theprocessor 14 detects the output voltage V_(AMP) of the differentialamplifier 15 and can calculate the resistance value R_(HTR) of theheater HT according to equations (2) and (4) and the temperature T ofthe heater HT according to equation (5). Note that the processor 14 maycalculate the temperature T of the heater HT according to one equationobtained by solving equations (2), (4), and (5) for the temperature T ormay calculate the temperature T of the heater HT according to anothermethod.

In step S907, the processor 14 turns off the second switch Q2. In thiscase, the processor 14 has a period in which the period during which thefirst switch Q1 is ON overlaps the period during which the second switchQ2 is ON. However, the processor 14 may control the first switch Q1 andthe second switch Q2 so as not to have a period in which the periodduring which the first switch Q1 is ON overlaps the period during whichthe second switch Q2 is ON. Having a period in which the period duringwhich the first switch Q1 is ON overlaps the period during which thesecond switch Q2 is ON allows the processor 14 to calculate thetemperature T of the heater HT with high frequency, thereby improvingthe accuracy of control executed by the processor 14 based on thetemperature T of the heater HT. Likewise, this will shorten the periodduring which the heater HT is not heated upon turning off of the firstswitch Q1, thereby facilitating delivering an aerosol having an intendedflavor to the user.

In step S908, the processor 14 determines whether the temperature T ofthe heater HT calculated in step S906 is lower than a predeterminedtemperature (threshold). If the processor 14 determines that thetemperature T of the heater HT is lower than the predeterminedtemperature, the process advances to step S910; otherwise, the processor14 can execute error processing in step S909. The error processing caninclude at least one of the following: displaying an error message onthe display DISP; inhibiting the heating of the heater HT; waiting forthe natural cooling of the heater HT; and analyzing an error cause (forexample, specifying an error cause based on the rise rate of thetemperature T of the heater HT).

In step S910, the processor 14 determines whether the suction detectedin step S901 has ended. If the processor 14 determined that the suctionhas ended, the process advances to step S911; otherwise, the processreturns to step S903. In step S911, the processor 14 stops theoperations of the third voltage converter (first regulator) 13 and thesecond voltage converter (second regulator) 12 by inactivating theenable signal EN2.

When the process returns from step S910 to step S903, the processor 14can determine the timing (of turning off the first switch Q1) of stepS905 thereafter based on the temperature T of the heater HT obtained inpreceding step S906. The timing (of turning off the first switch Q1) ofstep S905 can be determined by, for example, PID computation based onthe difference between the target temperature of the heater HT and thetemperature T of the heater HT obtained in preceding step S906 such thatthe temperature T of the heater HT approaches the target temperature.

According to one aspect, the electrical components 110 of the controller102 can include the connection terminal C1 to which the heater HT forheating the aerosol source of the atomizer 104 is connected, the controlcircuit CC for controlling the operation of the controller 102, thefirst voltage converter 11 for supplying a voltage to all or part of thecontrol circuit CC, and the second voltage converter 12 for supplying avoltage (second voltage V2) to the connection terminal C1. In this case,the first period in which the first voltage converter 11 operates candiffer from the second period in which the second voltage converter 12operates. Note that the periods in which the respective voltageconverters operate may be interpreted as periods in which voltagesconverted by starting the respective voltage converters can be output orperiods in which the voltages converted by the respective voltageconverters are output. In other words, the processor 14 can control thefirst voltage converter 11 and the second voltage converter 12 such thatthe first period differs from the second period. The processor 14 can beconfigured to control the first voltage converter 11 by, for example,using an enable signal EN1. The second period in which the secondvoltage converter 12 operates can be part of the first period in whichthe first voltage converter 11 operates. For example, the second periodcan be started after the start of the first period and before the end ofthe first period and can be ended before the end of the first period orat the end of the first period. This arrangement allows the processor 14to separately determine the first period and the second period inaccordance with a load (device) to be operated and hence is advantageousin reducing the power consumption of the inhaler 100 or the controller102.

The first voltage converter 11 can be formed by, for example, an LDO(Low DropOut). In addition, the second voltage converter 12 can beformed by, for example, an LDO (Low DropOut). The first voltageconverter 11 and the second voltage converter 12 may have the samespecifications or have different specifications. The former case cancontribute to a reduction in the manufacturing cost of the controller102 (the sourcing cost of components). The latter case enables theselection of loads (devices) requiring different performancesconcerning, for example, power supply voltage, and hence is advantageousin expanding the functionality of the inhaler 100 or the controller 102.

A more specific example of the latter case is that the number of loadsconnected to the output terminal of the first voltage converter 11 islarger than the number of loads connected to the output terminal of thesecond voltage converter 12. In the example shown in FIG. 2, the loadsconnected to the output terminal of the first voltage converter 11include the switch 20, the puff sensor 21, and the touch sensor 22,whereas the loads connected to the output terminal of the second voltageconverter 12 include the second path P2 (heater HT) and the differentialamplifier 15. In the example shown in FIG. 2, the LED driver 18 and theLED 19 are not connected to the output terminal of the second voltageconverter 12 but are connected to the external power supply EB via thepower supply BAT or the plug PG. In another example, the loads connectedto the output terminal of the first voltage converter 11 can include theLED driver 18, the LED 19, the switch 20, the puff sensor 21, and thetouch sensor 22, whereas the loads connected to the output terminal ofthe second voltage converter 12 can include the second path P2 (heaterHT) and the differential amplifier 15.

Alternatively, the total power consumption of the loads connected to theoutput terminal of the first voltage converter 11 is lower than thetotal power consumption of the loads connected to the output terminal ofthe second voltage converter 12. For example, in the example shown inFIG. 2, the total power consumption of the switch 20, the puff sensor21, and the touch sensor 22 connected to the output terminal of thefirst voltage converter 11 is lower than the total power consumption ofthe heater HT and the differential amplifier 15 connected to the outputterminal of the second voltage converter 12. This can be understood inconsideration of the main use of the inhaler 100 that delivers anaerosol having a flavor, more specifically, in consideration of the factthat the power consumption of the heater HT is high.

Alternatively, the self-current consumption of the first voltageconverter 11 is lower than the self-current consumption of the secondvoltage converter 12. The self-current consumption of the voltageconverter indicates the current consumed by the voltage converter toconvert the voltage (power) input to the input terminal of the voltageconverter into the voltage (power) output from the output terminal ofthe voltage converter. The self-current consumption can be referred fromthe data sheet of the voltage converter. The self-current consumptiongenerally varies in accordance with the specifications of voltageconverters. A lower self-current consumption indicates more efficientvoltage conversion. That is, a voltage converter with a lowerself-current consumption leads to the power saving of the power supplyBAT and can suppress the heating of the voltage converter. Inparticular, when the first period in which the first voltage converter11 operates is long (as compared with the second period in which thesecond voltage converter 12 operates), using a voltage converter with alow self-current consumption as the first voltage converter 11 isimportant in terms of power saving and suppressing the generation ofheat. In particular, the inhaler 100 that has achieved power savingincreases the amount of aerosol having a flavor that can be provided percharging of the power supply BAT, and hence can greatly improve itscommodity value.

Alternatively, the load transient response characteristic of the secondvoltage converter 12 may be superior to the load transient responsecharacteristic of the first voltage converter 11. The load transientresponse characteristic of a voltage converter is an index indicatinghow much time it takes for an output voltage set in a transient stateupon an abrupt increase or decrease in the output current of the voltagetransfer to be set in a steady state. A load transient responsecharacteristic is generally represented on the voltage basis. A smallerload transient response characteristic indicates that a steady state isset faster. This load transient response characteristic is especiallyimportant for a voltage converter that outputs a current or voltage onlyat the limited timing of acquiring the temperature T of the heater HT asin the first voltage converter 11. This is because, if the loadtransient response characteristic is not excellent, when the resistancevalue R_(HTR) (the temperature T of the heater HT) of the heater HT isto be acquired according to equation (2), the second voltage V2 outputfrom the second voltage converter 12 is difficult to exhibit a steadyvalue and it is necessary to keep the second voltage converter 12 activeuntil the second voltage V2 exhibits a steady value. In other words,using the second voltage converter 12 having an excellent load transientresponse characteristic allows the processor 14 to acquire theresistance value R_(HTR) (the temperature T of the heater HT) of theheater HT fast and accurately and can shorten the period during whichthe second voltage converter 12 operates, thereby achieving the powersaving of the inhaler 100.

The self-current consumption and the load transient responsecharacteristic of a general voltage converter tend to have a trade-offrelationship. A voltage converter with a low self-current consumptiontends to have a poor load transient response characteristic. Inaddition, a voltage converter with an excellent load transient responsecharacteristic tends to have a high self-current consumption.Accordingly, it is important how to deal with this trade-off inaccordance with the applications of voltage converters and the loads tobe connected to the output terminals. In this embodiment, although alarge number of loads are connected to the output terminal of the firstvoltage converter 11, the total power consumption is low and hence doesnot easily change abruptly. Since it is difficult for an output voltageto make a transition to a transient state, the requirement for anexcellent load transient response characteristic is low with respect tothe first voltage converter 11. In contrast to this, if the first periodin which the first voltage converter 11 operates is long (as comparedwith the second period in which the second voltage converter 12operates), the requirement for an excellent load transient responsecharacteristic is high with respect to the first voltage converter 11.That is, the first voltage converter 11 is preferably formed by avoltage converter with a low self-current consumption even if its loadtransient response characteristic is not excellent.

In this embodiment, although a small number of loads are connected tothe output terminal of the second voltage converter 12, the total powerconsumption is high and hence easily changes abruptly. Since an outputvoltage easily makes a transition to a transient state, the requirementfor an excellent load transient response characteristic is high withrespect to the first voltage converter 11. In contrast to this, if thesecond period in which the second voltage converter 12 operates is long(as compared with the first period in which the first voltage converter11 operates), the requirement for an excellent load transient responsecharacteristic is low with respect to the second voltage converter 12.That is, the second voltage converter 12 is preferably formed by avoltage converter with an excellent load transient responsecharacteristic even if the self-current consumption is high.

In other words, the first voltage converter 11 is preferably formed by avoltage converter that is lower in self-current consumption than thesecond voltage converter 12 and inferior in load transient responsecharacteristic to the second voltage converter 12. The second voltageconverter 12 is preferably formed by a voltage converter that is lowerin self-current consumption than the first voltage converter 11 andsuperior in load transient response characteristic to the first voltageconverter 11. In addition, the self-current consumption of the firstvoltage converter 11 is preferably lower than the self-currentconsumption of the second voltage converter 12. The load transientresponse characteristic of the second voltage converter 12 is preferablysuperior to the load transient response characteristic of the firstvoltage converter 11.

As exemplarily shown in FIGS. 3, 4, and 5, the controller 102 caninclude a first power supply path SL1 for supplying a voltage from thepower supply BAT to the first voltage converter 11, a second powersupply path SL2 for supplying a voltage from the power supply BAT to thesecond voltage converter 12, and a third power supply path SL3 forsupplying a voltage from the external power supply EB to the firstvoltage converter 11. In one point of view, power can be supplied fromboth the power supply BAT and the external power supply EB to the firstvoltage converter 11, whereas no power is supplied from the externalpower supply EB to the second voltage converter 12 even though power canbe supplied from the power supply BAT. This can suppress a deteriorationin the power supply BAT, which is charged with power supplied from theexternal power supply EB, caused when the heat generated upon theoperation of the second voltage converter 12 and the heater HT isapplied to the power supply BAT.

As exemplarily shown in FIG. 3, a first rectifier element SD may bearranged in the first power supply path SL1, and a voltage can besupplied from the power supply BAT to the first voltage converter 11 viathe first rectifier element SD. The first rectifier element SD can bearranged such that the direction from the power supply BAT to the firstvoltage converter 11 is the forward direction. The first rectifierelement SD can be, for example, a Schottky diode. The Schottky diodeuses contact between a semiconductor and a metal and is smaller inforward voltage drop than a PN junction diode, and hence is advantageousin supplying a voltage from the power supply BAT to the first voltageconverter 11. More specifically, supplying a voltage from the powersupply BAT to the first voltage converter 11 via the Schottky diode SDwill reduce the loss of power supplied from the power supply BAT ascompared with supplying a voltage from the power supply BAT to the firstvoltage converter 11 via a first body diode D3 of the first transistorQ3 (to be described later).

As exemplarily shown in FIG. 4, the positive terminal of the powersupply BAT can be electrically connected to the second voltage converter12 via the second power supply path SL2. The positive terminal of thepower supply BAT can be directly connected to the second voltageconverter 12 by using a conductive pattern (conductive trace). Inanother point of view, the positive terminal of the power supply BAT canbe electrically connected to the second voltage converter 12 without viaany electrical elements such as a resistor, a switch, and an IC. Thepositive terminal of the power supply BAT can also be electricallyconnected to the third voltage converter 13 via the second power supplypath SL2. This makes it possible to supply power from the power supplyBAT to the second voltage converter 12 and the third voltage converter13 with minimum loss of power.

The first transistor Q3 can be connected in parallel with the firstrectifier element SD. The first transistor Q3 can include the first bodydiode D3. The forward direction of the first body diode D3 can be thesame as the forward direction of the first Schottky diode SD. The powersupply BAT can be charged by the external power supply EB via the firsttransistor Q3.

As exemplarily shown in FIG. 5, a second rectifier element D4 can bearranged in the third power supply path SL3. A voltage can be suppliedfrom the external power supply EB to the first voltage converter 11 viathe second rectifier element D4. The second rectifier element D4 caninclude the second body diode provided for the second transistor Q4arranged in the third power supply path SL3. With this arrangement, thevoltage supplied from the external power supply EB undergoes a forwardvoltage drop by the second rectifier element D4 and is supplied to theinput terminal of the first voltage converter 11. When the first voltageconverter 11 is formed by a series regulator such as an LDO, an inputvoltage is stepped down by discarding extra power as heat and outputfrom the output terminal. For this reason, reducing the differencebetween an input voltage and an output voltage can further suppress thegeneration of heat by the first voltage converter 11. That is, since aforward voltage drop in the second rectifier element D4 steps down theinput voltage of the first voltage converter 11, the generation of heatby the first voltage converter 11 can be suppressed. In other words,since it is possible to prevent the generation of heat fromconcentrating in the first voltage converter 11 and disperse thegeneration of heat to the second rectifier element D4 and the firstvoltage converter 11, the durability of the inhaler 100 can be improved.After the voltage supplied from the external power supply EB via thesecond rectifier element D4 is supplied to the input terminal of thefirst voltage converter 11, the processor 14 may turn on the secondtransistor Q4 and turn on/off the first transistor Q3. This can supplythe voltage stepped down by the first transistor Q3 and the Schottkydiode SD to the input terminal of the first voltage converter 11 whilesuppressing the generation of heat in the second rectifier element D4,thereby improving the durability of the inhaler 100.

The source of the first transistor Q3 can be electrically connected tothe source of the second transistor Q4. In addition, the source of thefirst transistor Q3 can be electrically connected to the source of thesecond transistor Q4 and the power supply terminal (power receivingterminal) of the first voltage converter 11. As exemplarily shown inFIG. 6 as a charging path CL, the power supply BAT can be charged by theexternal power supply EB via the first transistor Q3 and the secondtransistor Q4. The second transistor Q4 can supply a voltage obtained bystepping down the voltage output from the protection circuit 16 to thefirst transistor Q3. The first transistor Q3 and the second transistorQ4 can form a charging circuit that charges the power supply BAT. Thiscan disperse the heat generated in the charging circuit to the firsttransistor Q3 and the second transistor Q4 and hence can improve thedurability of the inhaler 100. The first transistor Q3 and the secondtransistor Q4 can be connected in series with the path in which acharging current flows. The processor 14 can charge the power supply BATby turning on the second transistor Q4 and turning on or on/off thefirst transistor Q3. The processor 14 can control the charging of thepower supply BAT at high speed by switching on and off the secondtransistor Q4 at high speed. The charging path CL extends, for example,from the external power supply EB to the positive electrode of the powersupply BAT via the plug PG, the bridge circuit BC, the protectioncircuit 16, the second transistor Q4, and the first transistor Q3.

Referring to FIG. 7, the current path (the charging path CL) in a statein which the power supply BAT is charged is indicated by the grayarrows. Referring to FIG. 8, the current path (a discharge path DL) in astate in which the power supply BAT is discharged via the heater HT isindicated by the gray arrows. The controller 102 includes a first lineL1 connected to the positive electrode of the power supply BAT and asecond line L2 connected to the negative electrode of the power supplyBAT. The first line L1 and the second line L2 can be arranged to formpart of a closed circuit including the power supply BAT as a constituentelement.

In one aspect, the electrical components 110 of the controller 102 caninclude the power supply BAT, the connection terminal C1 to which theheater HT for heating the aerosol source of the atomizer 104 by using acurrent supplied from the power supply BAT is connected, the processor14, and the protection circuit 17. The processor 14 includes a detectorDP that detects a current supplied from the power supply BAT and/or acurrent supplied to the power supply BAT and can control the state ofthe power supply BAT based on the detection result obtained by thedetector DP. The protection circuit 17 includes a monitor MP thatmonitors the state of the power supply BAT and can protect the powersupply BAT based on the monitoring result obtained by the monitor MP.The protection circuit 17 can be provided separately from the processor14. This arrangement is advantageous in improving the protectionfunction of the power supply BAT and also the protection function of theinhaler 100.

The processor 14 can control the charging of the power supply BAT basedon the detection result obtained by the detector DP when the detector DPdetects a current supplied to the power supply BAT. More specifically,the processor 14 can control the first transistor Q3 and the secondtransistor Q4 described above, which form a charging circuit forcharging the power supply BAT, based on the detection result obtained bythe detector DP. In addition, when the detection result obtained by thedetector DP indicates abnormality, the processor 14 can stop chargingthe power supply BAT using the charging circuit (the first transistor Q3and the second transistor Q4). For example, when the detection resultobtained by the detector DP indicates abnormality, the processor 14 cancontrol the first transistor Q3 into the OFF state. When the firsttransistor Q3 is set in the OFF state, the electrical connection betweenthe external power supply EB and the power supply BAT is cut off to stopcharging the power supply BAT.

The third voltage converter (first regulator) 13 receives the voltagesupplied from the power supply BAT and generates the first voltage V1(driving voltage) for driving the heater HT so as to heat the aerosolsource of the atomizer 104. The second voltage converter (secondregulator) 12 receives the voltage supplied from the power supply BATand generates the second voltage V2 (measurement voltage) for measuringthe resistance value R_(HTR) of the heater HT. When the detector DPdetects the current supplied from the power supply BAT and the detectionresult obtained by the detector DP indicates abnormality, the processor14 can stop the operation of the third voltage converter (firstregulator) 13 and the second voltage converter (second regulator) 12 byinactivating the enable signal EN2. Alternatively, when the detector DPdetects the current supplied from the power supply BAT and the detectionresult obtained by the detector DP indicates abnormality, the processor14 may control the first switch Q1 in the OFF state or control the firstswitch Q1 and the second switch Q2 in the OFF state. Alternatively, thedetector DP detects the current supplied from the power supply BAT andthe detection result obtained by the detector DP indicates abnormality,the processor 14 controls the first switch Q1 and the second switch Q2in the OFF state while inactivating the enable signal EN2. In eithercase, the electrical connection between the power supply BAT and theheater HT is cut off, and hence discharging from the power supply BAT tothe heater HT is stopped. The mode of stopping discharging from thepower supply BAT to the heater HT by inactivating the enable signal EN2also stops the operation of the third voltage converter 13 and thesecond voltage converter 12, and hence is advantageous in power savingof the power supply BAT. The mode of stopping discharging to the heaterHT of the power supply BAT by controlling the first switch Q1 and thesecond switch Q2 in the OFF state is advantageous in terms of the speedof stopping the discharging because of small frequencies of current andvoltage transient responses as compared with the case of stopping theoperations of the third voltage converter 13 and the second voltageconverter 12. The mode of stopping discharging to the heater HT of thepower supply BAT by using both the inactivation of the enable signal EN2and control on the first switch Q1 and the second switch Q2 in the OFFstate is advantageous in terms of the capability to stop the dischargingat high probability even when either the voltage converter or the switchhas failed. When the detection result obtained by the detector DPindicates an overcurrent and the processor 14 handles the correspondingstate as abnormality, a short-circuit may have occurred in one of thefollowing: the first switch Q1, the second switch Q2, the third voltageconverter 13, and the second voltage converter 12. For this reason, inorder to reliably stop discharging to the heater HT of the power supplyBAT, it is important to perform both the inactivation of the enablesignal EN2 and control on the first switch Q1 and the second switch Q2in the OFF state.

The protection circuit 17 can include a switch SP arranged in the secondline L2 so as to be able to cut off the second line L2. The switch SP ispreferably formed by directly connecting two switches in differentdirections so as to be able to cut off a charging current for chargingthe power supply BAT and a discharge current discharged from the powersupply BAT. When the monitoring result obtained by the monitor MPindicates abnormality, the protection circuit 17 can cut off a currentsupplied from the power supply BAT and a current supplied to the powersupply BAT by turning off the switch SP. The protection circuit 17receives power from the first line L1.

The detector DP includes a first resistor R_(D). The monitor MP includesa second resistor R_(P). The first resistor R_(D) and the secondresistor R_(P) can be arranged in series with a path extending from thepositive electrode of the power supply BAT to its negative electrode.The first resistor R_(D) and the second resistor R_(P) can be arrangedto cause a current flowing from the positive electrode of the powersupply BAT to pass through the heater HT first and then pass through thefirst resistor R_(D) and the second resistor R_(P). Alternatively, thefirst resistor R_(D) and the second resistor R_(P) can be arranged inseries with the second line L2 (that is, so as to form part of thesecond line L2). High-side connection can be made between the firstresistor R_(D) and the second resistor R_(P) instead of such low-sideconnection between the first resistor R_(D) and the second resistorR_(P). In the high-side connection, the first resistor R_(D) and thesecond resistor R_(P) can be arranged to cause a current flowing outfrom the positive electrode of the power supply BAT to pass through thefirst resistor R_(D) and the second resistor R_(P) before passingthrough the heater HT. Alternatively, the first resistor R_(D) and thesecond resistor R_(P) can be arranged in series with the first line L1(that is, so as to form part of the first line L1). This indicates thatwhen the detector DP or the monitor MP includes a differential amplifier(operational amplifier), the common mode voltage of the differentialamplifier can be set low or 0. A lower common mode voltage increases thenumber of options for differential amplifiers, and hence is advantageousin terms of cost.

The detector DP detects a current flowing in the first resistor R_(D) ora voltage drop caused by the first resistor R_(D). The processor 14 candetect abnormality based on the detection result obtained by thedetector DP and stop the charging of the power supply BAT and/ordischarging from the power supply BAT to the heater HT. The monitor MPcan detect a current flowing in the second resistor R_(P) or a voltagedrop caused by the second resistor R_(P). The protection circuit 17 candetect abnormality based on the monitoring result obtained by themonitor MP and stop the charging of the power supply BAT and/ordischarging from the power supply BAT to the heater HT.

The condition by which the processor 14 stops the charging of the powersupply BAT can differ from the condition by which the protection circuit17 stops the charging of the power supply BAT. In addition, thecondition by which the processor 14 stops charging from the power supplyBAT can differ from the condition by which the protection circuit 17stops charging from the power supply BAT.

The controller 102 can include the thermistor TM having one terminalconnected between the negative electrode of the power supply BAT and theswitch SP in the second line L2. The thermistor TM is mainly used toacquire the temperature of the power supply BAT. The other terminal ofthe thermistor TM can be arranged to supply a voltage dependent on theresistance value of the thermistor TM to the processor 14. For example,the processor 14 supplies a predetermined voltage from an outputterminal VO to the thermistor TM via a resistor R5 and receives thevoltage divided by the resistor R5 and the thermistor TM at an inputterminal VI, thereby detecting the resistance value of the thermistorTM. The resistance value of the thermistor TM can provide informationindicating a temperature. When the thermistor TM is provided at thisposition, the output terminal VO is connected to the thermistor TM viathe resistor R5 and is then connected to the negative electrode of thepower supply BAT via the thermistor TM without via another element. Thismakes it difficult for noise to mix with a voltage input to the inputterminal VI and allows the processor 14 to acquire the temperature ofthe thermistor TM or the power supply BAT with high accuracy.

FIG. 10 exemplarily shows the operation of the protection circuit 17. Instep S1001, the protection circuit 17 initializes parameters i and j to0. In step S1001, the protection circuit 17 detects a current valuei_(P) (a charging current value at the time of charging or a dischargecurrent value at the time of discharging) flowing in the power supplyBAT by the monitor MP. In the following description, the current valuei_(P) is handled as an absolute value. Note that at both the time ofcharging and the time of discharging, the current value i_(P) indicatesonly a positive value, and its minimum value is 0. In step S1003, theprotection circuit 17 determines whether the current value i_(P) exceedsa first threshold i_(T1). If YES in step S1003, the process advances tostep S1004; otherwise, the process advances to step S1008. In detectionsignal step S1004, the protection circuit 17 adds 1 to the value of theparameter i. In step S1005, the protection circuit 17 determines whetherthe value of the parameter i is equal to or more than i_(max). If thevalue of the parameter i is equal to or more than i_(max), the processadvances to step S1006; otherwise, the process returns to step S1002. Inthis case, that the value of the parameter i is equal to or more thani_(max) indicates that the period during which the current value i_(P)has exceeded the first threshold i_(T1) has reached a first time t1(=i_(max)/f_(P)). Note that f_(P) is the period (sampling period) duringwhich step S1002 is executed. In step S1006, the protection circuit 17determines that an overcurrent (that is, abnormality) is detected, andthe process advances to step S1007.

In step S1008, the protection circuit 17 determines whether the currentvalue i_(P) exceeds a second threshold i_(T2) smaller than the firstthreshold i_(T1). If YES in step S1008, the process advances to stepS1009; otherwise, the process returns to step S1001. In step S1009, theprotection circuit 17 adds 1 to the value of the parameter j. In stepS1010, the protection circuit 17 determines whether the value of theparameter j is equal to or more than j_(max). If the value of theparameter j is equal to or more than j_(max), the process advances tostep S1011; otherwise, the process returns to step S1002. In this case,that the value of the parameter j is equal to or more than j_(max)indicates that the period during which the current value i_(P) hasexceeded the second threshold i_(T2) has reached a second time t2(=j_(max)/f_(P)) longer than the first time t1 (=i_(max)/f_(P)). In stepS1011, the protection circuit 17 determines that an overcurrent (thatis, abnormality) has been detected. The process then advances to stepS1007. In step S1007, the protection circuit 17 cuts off a currentsupplied from the power supply BAT and/or a current supplied to thepower supply BAT by turning off the switch SP. This indicates that ifthe power supply BAT has been charged, the charging is stopped, whereasif the power supply BAT has been discharged, the discharging is stopped.This embodiment has exemplified the case in which the first thresholdi_(T1), the second threshold i_(T2), i_(max), and j_(max) are common toa charging operation and a discharging operation. Instead of thissetting, at least one of the first threshold i_(T1), the secondthreshold i_(T2), i_(max), and j_(max) may differ between a chargingoperation and a discharging operation. In addition, the sampling periodf_(P) may differ between a charging operation and a dischargingoperation.

FIG. 11 exemplarily shows the operation of the processor 14. In stepS1101, the processor 14 initializes the parameters k and l to 0. In stepS1102, the processor 14 detects a current value i_(D) (a chargingcurrent value at the time of charging or a discharge current value atthe time of discharging) flowing in the power supply BAT. In thefollowing description, the current value i_(D) is handled as an absolutevalue. Note that the current value i_(D) indicates only a positive valueand its minimum value is 0 at both the time of charging and the time ofdischarging. In step S1103, the processor 14 determines whether thecurrent i_(D) exceeds a third threshold in. If YES in step S1103, theprocess advances to step S1104; otherwise, the process advances to stepS1108. In step S1104, the processor 14 adds 1 to the value of theparameter k. In step S1105, the processor 14 determines whether thevalue of the parameter k is equal to or more than k_(max). If the valueof the parameter k is equal to or more than k_(max), the processadvances to step S1106; otherwise, the process returns to step S1102. Inthis case, that the value of the parameter k is equal to or more thank_(max) indicates that the period during which the current value i_(D)has exceeded the third threshold in has reached a third time t3(=k_(max)/f_(D)). Note that f_(D) is a period (sampling period) in whichstep S1102 is executed. In step S1106, the processor 14 determines thatan overcurrent (that is, abnormality) is detected. The process thenadvances to step S1107.

In step S1108, the processor 14 determines whether the current valuei_(D) exceeds a fourth threshold i_(T4) smaller than the third thresholdin. If YES in step S1108, the process advances to step S1109; otherwise,the process returns to step S1101. In step S1109, the processor 14 adds1 to the value of the parameter 1. In step S1110, the processor 14determines whether the value of the parameter 1 is equal to or more thanl_(max). If the value of the parameter 1 is equal to or more thanl_(max), the process advances to step S1111; otherwise, the processreturns to step S1102. In this case, that the value of the parameter 1is equal to or more than l_(max) indicates that the period during whichthe current i_(D) exceeds the fourth threshold i_(T4) has reached afourth time t4 (=l_(max)/f_(D)) longer than a third time t3(=k_(max)/f_(D)). In step S1111, the processor 14 determines that anovercurrent (that is, abnormality) has been detected. The process thenadvances to step S1107. In step S1107, the processor 14 cuts off acurrent supplied from the power supply BAT and/or a current supplied tothe power supply BAT. This operation can be implemented by, for example,turning off the first transistor Q3 when the power supply BAT has beencharged, and can be implemented by, for example, inactivating the enablesignal EN2 when the power supply BAT has been discharged. Note that theprocessor 14 may control the first switch Q1 and the second switch Q2 inthe OFF state instead of or in addition to inactivating the enablesignal EN2 as described above. This embodiment has exemplified the casein which the third threshold in, the fourth threshold i_(T4), k_(max),and l_(max) serving as thresholds are common to a charging operation anda discharging operation. However, at least one of the third thresholdin, the fourth threshold i_(T4), k_(max), and l_(max) may differ betweena charging operation and a discharging operation. In addition, thesampling period f_(D) may differ between a charging operation and adischarging operation.

FIG. 12 exemplarily shows the relationship among the first thresholdi_(T1), the second threshold i_(T2), the third threshold i_(T3), thefourth threshold i_(T4), the first time t1, the second time t2, thethird time t3, and the fourth time t4. As described above, the firstthreshold i_(T1), the second threshold i_(T2), the first time t1, andthe second time t2 are criteria based on which the protection circuit 17determines whether to charge and discharge the power supply BAT. Thethird threshold in, the fourth threshold i_(T4), the third time t3, andthe fourth time t4 are criteria based on which the processor 14determines whether to charge and discharge the power supply BAT. Thefirst threshold i_(T1) and the first time t1 are criteria for detectingthat a large current (for example, on the ampere order) flowsinstantaneously (for example, on the microsecond order). Likewise, thethird threshold in and the third time t3 are criteria for detecting thata large current (for example, on the ampere order) flows instantaneously(for example, on the microsecond order). On the other hand, the secondthreshold i_(T2) and the second time t2 are criteria for detecting thata small current (for example, on the sub-ampere order) flows for a longperiod of time (for example, on the second order). Likewise, the fourththreshold i_(T4) and the fourth time t4 are criteria for detecting thata small current (for example, on the sub-ampere order) flows for a longperiod of time (for example, on the second order).

For example, the processor 14 determines the occurrence of abnormalityin accordance with a criterion stricter than that set for the protectioncircuit 17. This operation can be implemented by setting the thirdthreshold in to a value smaller than the first threshold i_(T1) andlarger than the second threshold i_(T2), setting the fourth thresholdi_(T4) to a value smaller than the second threshold i_(T2), setting thethird time t3 to a time shorter than the first time t1, and setting thefourth time t4 to a time longer than the first time t1 and shorter thanthe second time t2.

According to the criteria exemplarily shown in FIG. 12, the protectioncircuit 17 stops the charging of the power supply BAT when the chargingcurrent value of the power supply BAT exceeds the first threshold i_(T1)under monitoring over the first time t1 and when the charging currentexceeds the second threshold i_(T2) smaller than the first thresholdi_(T1) under monitoring over the second time t2 longer than the firsttime t1. The processor 14 also stops the charging of the power supplyBAT when the charging current value exceeds the third threshold insmaller than the first threshold i_(T1) and larger than the secondthreshold i_(T2) in detection over the third time t3 shorter than thefirst time t1 and when the charging current exceeds the fourth thresholdi_(T4) smaller than the second threshold i_(T2) in detection over thefourth time t4 shorter than the second time t2.

According to the criteria exemplarily shown in FIG. 12, the protectioncircuit 17 stops discharging from the power supply BAT when thedischarge current value of the power supply BAT exceeds the firstthreshold i_(T1) under monitoring over the first time t1 and when thedischarge current value exceeds the second threshold i_(T2) smaller thanthe first threshold i_(T1) under monitoring over the second time t2longer than the first time t1. The processor 14 also stops dischargingfrom the power supply BAT when the discharge current value exceeds thethird threshold in smaller than the first threshold i_(T1) and largerthan the second threshold i_(T2) in detection over the third time t3shorter than the first time t1 and when the discharge current exceedsthe fourth threshold i_(T4) smaller than the second threshold i_(T2) indetection over the fourth time t4 longer than the first time t1 andshorter than the second time t2.

Assume that a commercially available protection IC is used as theprotection circuit 17. In this case, when the first threshold i_(T1),the second threshold i_(T2), i_(max), and j_(max) in many protection ICsare changed from predetermined initial values to other values, theinside of each protection IC must be changed. Accordingly, when acommercially available protection IC is used as the protection circuit17, there are limitations on the determination of the occurrence ofabnormality according to strict criteria different from thespecification of the protection IC. In contrast to this, the thirdthreshold i_(T3), the fourth threshold i_(T4), k_(max), and l_(max) usedby the processor 14 can be relatively easily changed from the writeterminal of the processor 14 or the like. Accordingly, in thisembodiment, the processor 14 determines the occurrence of abnormalityaccording to strict criteria (stricter than the protection circuit 17)to improve the protection function of the inhaler 100. That theprocessor 14 determines the occurrence of abnormality according tocriteria stricter than those in the protection circuit 17 corresponds tothat the processor 14 and the protection circuit 17 independently anddoubly determine the occurrence of abnormality under appropriatecriteria, respectively. This also improves the protection function ofthe inhaler 100.

Pay attention to targets that are operated by the protection circuit 17and the processor 14 to cut off a current supplied from the power supplyBAT and/or a current supplied to the power supply BAT. As describedabove, the protection circuit 17 operates the switch SP to cut off acurrent supplied from the power supply BAT and/or a current supplied tothe power supply BAT. The processor 14 operates at least one of thethird voltage converter 13, the second voltage converter 12, the firstswitch Q1, and the second switch Q2 to cut off a current supplied fromthe power supply BAT. In addition, the processor 14 operates the firsttransistor Q3 to cut off a current supplied to the power supply BAT. Asdescribed above, the protection circuit 17 and the processor 14 operatedifferent targets to cut off a current supplied from the power supplyBAT and/or a current supplied to the power supply BAT. Under acircumstance in which an overcurrent is generated, a trouble may haveoccurred in any of the elements forming the electrical components 110.Assume that the protection circuit 17 and the processor 14 haverespectively determined the occurrence of abnormality according todifferent criteria described above. Even in this case, when theprotection circuit 17 and the processor 14 operate the same target, theoccurrence of a trouble in the target (element) makes it difficult toproperly protect the inhaler 100. Making the protection circuit 17 andthe processor 14 operate different targets facilitates avoiding such asituation. This makes it possible to further improve the protectionfunction of the inhaler 100.

The second time t2 and the fourth time t4 can be set as times longerthan the time during which a current can be supplied from the powersupply BAT to the heater HT in response to a first aerosol requestingoperation (puff operation). Specifically, the second time t2 and thefourth time t4 can be set to times longer than the time during which thesupply of a current from the power supply BAT to the heater HT isforcibly stopped even if the detection of one first aerosol requestingoperation (puff operation) continues. In addition, the first thresholdi_(T1) and the third threshold in can be values larger than a currentvalue flowing in the second line L2 in steps S903 to S906 in a normalstate. Furthermore, the second threshold i_(T2) and the fourth thresholdi_(T4) can be values larger than a current value flowing in the secondline L2 in steps S903 to S906 in a normal state.

The invention is not limited to the foregoing embodiments, and variousvariations/changes are possible within the spirit of the invention.

What is claimed is:
 1. An inhaler controller comprising: a first pathconfigured to connect, via a first switch, a first voltage terminal towhich a first voltage is supplied and a connection terminal to which aheater configured to heat an aerosol source is connected; a second pathconfigured to connect, via a second switch, a second voltage terminal towhich a second voltage different from the first voltage is supplied andthe connection terminal via a resistor; and a measurement circuitconfigured to measure a resistance value of the heater, wherein avoltage of the first voltage terminal is different from a voltage of thesecond voltage terminal, the first voltage is a voltage for heating theheater, and the second voltage is a voltage for measuring the resistancevalue of the heater.
 2. The controller according to claim 1, furthercomprising a cutoff unit configured to cut off a current flowing betweenthe first path and the second path due to a difference between the firstvoltage and the second voltage.
 3. The controller according to claim 2,wherein the cutoff unit includes a diode.
 4. The controller according toclaim 3, wherein the cutoff unit is arranged in the second path.
 5. Thecontroller according to claim 4, wherein the measurement circuitincludes a differential amplifier arranged to detect a voltage dropcaused by the heater.
 6. The controller according to claim 5, wherein avoltage is supplied from a node between the second voltage terminal andthe cutoff unit to a power supply terminal of the differentialamplifier.
 7. The controller according to claim 5, wherein thedifferential amplifier includes a first input terminal to which avoltage corresponding to a voltage of the connection terminal issupplied and a second input terminal to which a predetermined voltage issupplied.
 8. The controller according to claim 7, further comprising aprotection element connected to the first input terminal.
 9. Thecontroller according to claim 8, wherein the protection element includesone of a Zener diode and a varistor.
 10. The controller according toclaim 1, further comprising: a first regulator configured to generatethe first voltage; and a second regulator configured to generate thesecond voltage.
 11. The controller according to claim 10, furthercomprising a processor configured to control the first regulator and thesecond regulator.
 12. The controller according to claim 11, wherein theprocessor controls the first regulator and the second regulator using acommon enable signal.
 13. The controller according to claim 11, whereinthe processor controls a magnitude of a voltage generated by the firstregulator.
 14. The controller according to claim 11, wherein theprocessor controls the first switch and the second switch.
 15. Thecontroller according to claim 14, wherein the processor has a period inwhich a period during which the first switch is ON overlaps a periodduring which the second switch is ON.